There was a moment between games in the second set of the Australian Open final when Rafael Nadal buried his head in his hands. His shoulders seemed to hunch. The pain that had been in evidence before the match had intensified to the point where his serve had almost slowed to a standstill. The commentators anticipated an imminent default. “It looks like a question of when rather than if,” they said.

Nadal didn’t default, however. He kept battling, all the way until the last point. Some have speculated that his appetite to continue was founded upon the possibility, however remote,